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• Undefined reference, using FFMpeg-library (AvCodec) on Ubuntu, 64-bits system

  5 mai 2012, par Anders Branderud

  I am running the example code of the latest FFMpeg-library.
  I have inserted the example code into the file videofecencoder.c :

  /*
  
  * copyright (c) 2001 Fabrice Bellard
  
  *
  
  * This file is part of Libav.
  
  *
  
  * Libav is free software; you can redistribute it and/or
  
  * modify it under the terms of the GNU Lesser General Public
  
  * License as published by the Free Software Foundation; either
  
  * version 2.1 of the License, or (at your option) any later version.
  
  *
  
  * Libav is distributed in the hope that it will be useful,
  
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  
  * Lesser General Public License for more details.
  
  *
  
  * You should have received a copy of the GNU Lesser General Public
  
  * License along with Libav; if not, write to the Free Software
  
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  
  */
  
  #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
  
  
  
  
  
  #include 
  
  #include 
  
  #include 
  
  
  
  #ifdef HAVE_AV_CONFIG_H
  
  #undef HAVE_AV_CONFIG_H
  
  #endif
  
  
  
  #include "libavutil/imgutils.h"
  
  #include "libavutil/opt.h"
  
  #include "libavcodec/avcodec.h"
  
  #include "libavutil/mathematics.h"
  
  #include "libavutil/samplefmt.h"
  
  
  
  #define INBUF_SIZE 4096
  
  #define AUDIO_INBUF_SIZE 20480
  
  #define AUDIO_REFILL_THRESH 4096
  
  
  
  /*
  
  * Video encoding example
  
  */
  
  static void video_encode_example(const char *filename, int codec_id)
  
  {
  
     AVCodec *codec;
  
     AVCodecContext *c= NULL;
  
     int i, out_size, size, x, y, outbuf_size;
  
     FILE *f;
  
     AVFrame *picture;
  
     uint8_t *outbuf;
  
     int nrOfFramesPerSecond  =25;
  
     int nrOfSeconds =1;
  
  
  
  
  
     printf("Video encoding\n");
  
  
  
     /* find the mpeg1 video encoder */
  
     codec = avcodec_find_encoder((CodecID) codec_id);
  
     if (!codec) {
  
         fprintf(stderr, "codec not found\n");
  
         exit(1);
  
     }
  
  
  
     c = avcodec_alloc_context3(codec);
  
     picture= avcodec_alloc_frame();
  
  
  
     /* put sample parameters */
  
     c->bit_rate = 400000;
  
     /* resolution must be a multiple of two */
  
     c->width = 352;
  
     c->height = 288;
  
     /* frames per second */
  
     c->time_base= (AVRational){1,25};
  
     c->gop_size = 10; /* emit one intra frame every ten frames */
  
     c->max_b_frames=1;
  
     c->pix_fmt = PIX_FMT_YUV420P;
  
  
  
     if(codec_id == CODEC_ID_H264)
  
         av_opt_set(c->priv_data, "preset", "slow", 0);
  
  
  
     /* open it */
  
     if (avcodec_open2(c, codec, NULL) < 0) {
  
         fprintf(stderr, "could not open codec\n");
  
         exit(1);
  
     }
  
  
  
     f = fopen(filename, "wb");
  
     if (!f) {
  
         fprintf(stderr, "could not open %s\n", filename);
  
         exit(1);
  
     }
  
  
  
     /* alloc image and output buffer */
  
     outbuf_size = 100000;
  
     outbuf = (uint8_t*) malloc(outbuf_size);
  
  
  
     /* the image can be allocated by any means and av_image_alloc() is
  
      * just the most convenient way if av_malloc() is to be used */
  
     av_image_alloc(picture->data, picture->linesize,
  
                    c->width, c->height, c->pix_fmt, 1);
  
  
  
     /* encode 1 second of video */
  
     int nrOfFramesTotal = nrOfFramesPerSecond * nrOfSeconds;
  
  
  
     /* encode 1 second of video */
  
     for(i=0;i < nrOfFramesTotal; i++) {
  
         fflush(stdout);
  
         /* prepare a dummy image */
  
         /* Y */
  
         for(y=0;yheight;y++) {
  
             for(x=0;xwidth;x++) {
  
                 picture->data[0][y * picture->linesize[0] + x] = x + y + i * 3;
  
             }
  
         }
  
  
  
         /* Cb and Cr */
  
         for(y=0;yheight/2;y++) {
  
             for(x=0;xwidth/2;x++) {
  
                 picture->data[1][y * picture->linesize[1] + x] = 128 + y + i * 2;
  
                 picture->data[2][y * picture->linesize[2] + x] = 64 + x + i * 5;
  
             }
  
         }
  
  
  
         /* encode the image */
  
         out_size = avcodec_encode_video(c, outbuf, outbuf_size, picture);
  
         printf("encoding frame %3d (size=%5d)\n", i, out_size);
  
         fwrite(outbuf, 1, out_size, f);
  
     }
  
  
  
     /* get the delayed frames */
  
     for(; out_size; i++) {
  
         fflush(stdout);
  
  
  
         out_size = avcodec_encode_video(c, outbuf, outbuf_size, NULL);
  
         printf("write frame %3d (size=%5d)\n", i, out_size);
  
         fwrite(outbuf, 1, out_size, f);
  
     }
  
  
  
     /* add sequence end code to have a real mpeg file */
  
     outbuf[0] = 0x00;
  
     outbuf[1] = 0x00;
  
     outbuf[2] = 0x01;
  
     outbuf[3] = 0xb7;
  
     fwrite(outbuf, 1, 4, f);
  
     fclose(f);
  
     free(outbuf);
  
  
  
     avcodec_close(c);
  
     av_free(c);
  
     av_free(picture->data[0]);
  
     av_free(picture);
  
     printf("\n");
  
  }
  
  
  
  int main(int argc, char **argv)
  
  {
  
     const char *filename;
  
  
  
     /* register all the codecs */
  
     avcodec_register_all();
  
  
  
     if (argc <= 1) {
  
  
  
         video_encode_example("/grb_1.mpg", CODEC_ID_MPEG1VIDEO);
  
     } else {
  
         filename = argv[1];
  
     }
  
  
  
  
  
     return 0;
  
  }

  When I run gcc videofecencoder.cc -lavcodec I get the following error messages :

  /tmp/ccJg8IDy.o: In function `video_encode_example(char const*, int)':
  
  videofecencoder.cc:(.text+0x35): undefined reference to `avcodec_find_encoder(CodecID)'
  
  videofecencoder.cc:(.text+0x74): undefined reference to `avcodec_alloc_context3(AVCodec*)'
  
  videofecencoder.cc:(.text+0x7d): undefined reference to `avcodec_alloc_frame()'
  
  videofecencoder.cc:(.text+0x113): undefined reference to `av_opt_set(void*, char const*, char const*, int)'
  
  videofecencoder.cc:(.text+0x12b): undefined reference to `avcodec_open2(AVCodecContext*, AVCodec*, AVDictionary**)'
  
  videofecencoder.cc:(.text+0x1f0): undefined reference to `av_image_alloc(unsigned char**, int*, int, int, PixelFormat, int)'
  
  videofecencoder.cc:(.text+0x35c): undefined reference to `avcodec_encode_video(AVCodecContext*, unsigned char*, int, AVFrame const*)'
  
  videofecencoder.cc:(.text+0x3cf): undefined reference to `avcodec_encode_video(AVCodecContext*, unsigned char*, int, AVFrame const*)'
  
  videofecencoder.cc:(.text+0x47c): undefined reference to `avcodec_close(AVCodecContext*)'
  
  videofecencoder.cc:(.text+0x488): undefined reference to `av_free(void*)'
  
  videofecencoder.cc:(.text+0x497): undefined reference to `av_free(void*)'
  
  videofecencoder.cc:(.text+0x4a3): undefined reference to `av_free(void*)'
  
  /tmp/ccJg8IDy.o: In function `main':
  
  videofecencoder.cc:(.text+0x4c3): undefined reference to `avcodec_register_all()'
  
  collect2: ld returnerade avslutningsstatus 1

  The command nm libavcodec.a | grep avcodec_find results in :

  00000000000008e0 T avcodec_find_best_pix_fmt
  
  0000000000000740 T avcodec_find_best_pix_fmt2
  
                   U avcodec_find_encoder
  
  0000000000002ca0 T avcodec_find_decoder
  
  0000000000002cf0 T avcodec_find_decoder_by_name
  
  0000000000002bd0 T avcodec_find_encoder
  
  0000000000002c30 T avcodec_find_encoder_by_name

  I also have another similar error with another library :
  Undefined reference despite linking in OpenFEC-library

  My system : Ubuntu 11, 64-bits machine

  My next step is to try to compile it on VirtualBox with Ubuntu 32 bits (running on a Windows-OS).

• PHP ffmpeg fetch metadata missing title, author, comment, artist

  19 avril 2012, par chrismacp

  I've been trying to fetch remote mp3 (and other format) meta data using the php5-ffmpeg extension.

  It is working although I am always missing the title, author, comment, artist details.

  I've been scouring the web for an answer but not found any solution.

  I did find this patch http://cvs.pld-linux.org/cgi-bin/viewvc.cgi/cvs/packages/php-ffmpeg/tests-metadata-api.patch which I thought may solve the problem, but I've been unable to compile php-ffmpeg even without the patch so haven't been able to work out if it will fix the problem.

  It seems this extension was abandoned a couple of years ago so I'm not holding out much hope of getting this working.

  Does anyone have any ideas of how to get remote meta data from audio video files using other tools ?

  I am thinking of just parsing the output of ffmpeg itelf using the '-i' option as this does return the correct meta data. Just a bit wary of calling exec in PHP for security reasons.

• SOLVED - Compiling FFMPEG on Windows with Cywin and NDK r5

  19 mai 2012, par protectedmember

  This isn't a question - it's an answer for alll of you who have been facing the same problems as I have. I've been trying to compile this thing for a while now and I know of the numerous posts floating around the internet offering help. I have read and tried most of the suggestions and wanted to colate my success into this single post for others to benefit from.

  Since I don't have a blog, I thought it wouldn't hurt to post on here instead.

  I have managed to compile FFMPEG 0.10.3 (Freedom) on Windows 7 (32 bit) using NDK r5 and Cygwin. The steps :

  1 - Download/install Cygwin in the root of your C drive. I'm not going to give instructions on this, it's simple enough and there are plenty of tutorials on this.

  2 - Download NDK r5 from here and extract to the root of your C drive.

  3 - Download FFMPEG 0.10.3 from here and extract to the root of your C drive.

  4 - Open the file 'configure' in the root of the FFMPEG directory in a text editor.

  5 - Comment out lines 2073, 2074 and 2075.

  6 - Below 2075, add the following line :

  TMPDIR=c :/cygwin/tmp

  7 - Download this script (thankyou roman10) and place it inside your FFMPEG root directory. Rename the file to

  build_android.sh

  8 - Open the script in a text editor and edit line 17 to read

  c :/android-ndk-r5

  9 - Click start > run and type "bash" (without the speech marks) and press enter.

  10 - Type the following and press enter :

  cd /cygdrive/c/ffmpeg-0.10.3

  11 - Type the following and press enter :

  ./build_android.sh

  12 - Sit back and wait... libffmpeg.so will soon appear in your "c :\ffmpeg-0.10.3\android\" directory (where is defined in the bottom of the script from roman10's blog). The default architecture is armv7-a.

  The script from roman10's blog will actually compile quite a large shared object (.so) file. The compiler flags can be adjusted to suit your needs in the script from roman10's blog.

  I hope this helps,

  P.